Referring to JP-7-190732A, for example, a vehicle is provided with a collision detection sensor (collision detection device) having an optical fiber member. The optical fiber member is attached to a front bumper of the vehicle, and protrudes to an outer side of the front bumper. The optical fiber member is provided with a light-emitting member and a light-receiving member which are respectively arranged at two longitudinal-direction ends of the optical fiber member. When the vehicle collides with an obstacle, a collision load will be exerted at the optical fiber member, so that the optical fiber member is deformed to cause a variation of a light-receiving amount of the light-receiving member. Thus, the collision detection sensor generates a collision signal based on the variation of the light-receiving amount.
However, in this case, because the optical fiber member protrudes toward the outer side of the vehicle, a fault of the optical fiber member can be caused when the impact in the collision is relatively large.
Referring to JP-5-45372A, a collision detection sensor having an optical fiber member and a urethane resin member is provided. The optical fiber member is fixed inside the urethane resin member having a long prism shape. In this case, the fault of the optical fiber member can be restricted even when the collision load is large.
However, the optical fiber member is to be disposed in the urethane resin member. Because the optical fiber member has a long shape which is similar to that of the urethane resin member, it is difficult to arrange the optical fiber member at a predetermined position in the urethane resin member. Thus, the manufacture of the collision detection sensor is complicated.